Variable temperature seat climate control system

ABSTRACT

A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a temperature switch and a fan switch, respectively. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control algorithm designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

Application Ser. No. 09/621,258 was filed Jul. 20, 2000 as acontinuation of the present case, and is now abandoned.

FIELD OF THE INVENTION

The present invention relates generally to a variable temperature seatand, more specifically, to a method and apparatus for controlling theflow and temperature of a heating or cooling medium through the seat toan occupant positioned in such seat.

BACKGROUND OF THE INVENTION

Cooling or heating occupants of buildings, homes, automobiles and thelike is generally carried out by convection through modifying thetemperature of air surrounding the occupants environment. Theeffectiveness of convection heating or cooling is largely dependent onthe ability of the temperature conditioned air to contact and surroundall portions of the occupants's body. Heating and cooling occupantsthrough convention is generally thought to be efficient in suchapplications as homes, offices, and other like structures where theoccupants are not stationary or fixed in one position but, rather aremoving around allowing maximum contact with the temperature treated air.

In other applications such as automobiles, planes, buses and the like,the occupants are typically fixed in one position with a large portionof their body's surface against the surface of a seat, isolated fromeffects of the temperature conditioned air. In such applications the useof distributing temperature conditioned air into the cabin of thevehicle to heat or cool the occupant is less effective due to thesomewhat limited surface area of contact with the occupant's body. Inaddition, oftentimes the surface of the seat is at a temperature closeto the ambient temperature upon initial contact by the occupant,increasing the need to provide rapid temperature compensation to theoccupant in an effective manner.

To address the problem of providing effective occupant heating orcooling in such applications, seats have been constructed to accommodatethe internal flow of a heating or cooling medium and to distribute thesame through the seating surface to the surface of the occupant incontact with the seat. A preferred heating and cooling medium is air. Aseat constructed in this manner increases the efficiency of heating orcooling a passenger by convection by distributing temperatureconditioned air directly to the surface the occupant generally isolatedfrom contact with temperature conditioned air that is distributedthroughout the cabin of the vehicle.

U.S. Pat. No. 4,923,248 issued to Feher discloses a seat pad andbackrest comprising an internal plenum for distributing temperatureconditioned air from a Peltier thermoelectric module through the surfaceof the seat pad and to an adjacent surface of an occupant. Thetemperature conditioned air is provided by using a fan to blow ambientair over the fins of a Peltier module. The heating or cooling of theoccupant is achieved by changing the polarity of the electricity thatpowers the Peltier module.

U.S. Pat. No. 5,002,336 issued to Feher discloses a joined seat andbackrest construction comprising an internal plenum for receiving anddistributing temperature conditioned air through the seat and to anadjacent surface of an occupant. Like U.S. Pat. No. 4,923,248, thetemperature conditioned air is provided by a Peltier thermoelectricmodule and distributed through the internal plenum by an electric fan.

U.S. Pat. No. 5,117,638 issued to Feher discloses a selectively cooledor heated seat construction and apparatus for providing temperatureconditioned air. The seat construction comprising, an internal plenum, aplastic mash layer, a metal mesh layer, and perforated outer layer. Theapparatus for providing the temperature conditioned air is heatexchanger comprising a Peltier thermoelectric module and a fan. Heatingor cooling the occupant is achieved by switching the polarity of theelectricity powering the Peltier module.

The seat constructions known in the art, although addressing the need toprovide a more efficient method of heating or cooling the occupant, hasnot addressed the need to provide temperature conditioned air to anoccupant in a manner that both maximizes occupant comfort and maximizespower efficiency.

The ever increasing awareness of our environment and the need toconserve resources has driven the need to replace hydrocarbon poweredvehicles, such as the automobile, with vehicles that are powered by anenvironmentally friendly power sources such as electricity. Thereplacement of current hydrocarbon automobiles with electric poweredvehicles will only become a reality if the electric powered vehicle canbe operated and maintained in a manner equaling or bettering that of thehydrocarbon powered automobile it replaces. Accordingly, the need forelectric vehicles to perform in an electrically efficient manner, isimportant to the success of the electric vehicle.

In order to maximize the electrical efficiency of the electric poweredvehicle it is necessary that the electrically powered ancillarycomponents of the electric vehicle function at maximum electricalefficiency. The seats known in the art that provide temperatureconditioned air to an occupant do not operate in an electricallyefficient manner. The temperature of the air being conditioned by thePeltier thermoelectric devices in such seats is adjusted by dissipatingthe excess power through a resister, i.e., by using a potentiometer. Thepractice of dissipating excess power instead of providing only thatamount of power necessary to operate the Peltier thermoelectric devicesmakes such seats unsuited for such power sensitive applications as theelectric vehicle as well as other applications where electricalefficiency is a concern.

The seats known in the art constructed to provided temperatureconditioned air to an occupant are adjustable in that the occupant mayeither choose to produce heated air or cooled air. However, the seatsknown in the art are unable to automatically regulate the temperature orflow rate of the cool or heated air distributed to the occupant in theevent that the thermoelectric device malfunctions or in the event thatthe user falls asleep. An electrical malfunctioning of thethermoelectric device could result in the abnormal heating of thedevice, causing damage to the thermoelectric device itself. Anelectrical malfunction could result in the distribution of hot air tothe occupant, causing discomfort or even injury. Additionally, aninitial temperature setting of maximum heat or maximum cold that is leftuntouched in the event the occupant falls asleep may cause damage to thethermoelectric device itself or may cause discomfort or even injury tothe occupant.

The seats known in the art, while able to vary the distribution of airto the seat bottom or seat back via occupant adjustment, do not allowthe occupant to vary the temperature of the air passing through the seatback or seat bottom, independently. The option of being able toselectively heat one portion of the seat and cool the other may bedesirable where the occupant requires such selective treatment due to aparticular medical condition or injury. For example, one a cold day itwould be desirable to distribute heated air to the seat back foroccupant comfort and cooled air to the seat bottom to assist in healinga leg injury that has recently occurred.

It is, therefore, desirable that a variable temperature seat comprise acontrol system and method for regulating the temperature and flow rateof temperature conditioned air to an occupant sitting in the seat. It isdesirable that the control system operate the seat in an electricallyefficient manner, making it ideal for use in power sensitiveapplications such as the electric powered vehicle. It is desirable thatthe control system operate the seat in a manner eliminating thepossibility of equipment damage, occupant discomfort or injury. It isalso desirable that the control system permit the independentdistribution of heated or cooled air to the seat back or seat bottom.

SUMMARY OF THE INVENTION

There is, therefore, provided in practice of this invention atemperature climate control system for use with a variable temperatureseat. The temperature climate control system comprises a variabletemperature seat suitable for distributing temperature conditioned airto a seated occupant, at least one heat pump for temperatureconditioning ambient air and passing the air to the seat, a temperaturesensor located at each heat pump, and a controller configured to monitorthe temperature of the heat pumps and regulate their operation accordingto a temperature climate control algorithm.

Each heat pump comprises a number of Peltier thermoelectric modules forselectively heating or cooling ambient air in a main heat exchanger. Theheated or cooled air is passed to the seat by a main exchanger fan. Eachheat pump also comprises a waste heat exchanger for removing unwantedheat or cooling from the Peltier modules. The unwanted heat or coolingis passed to the outside environment by a waste exchanger fan.

Each main fan may be manually adjusted to operate at a variety ofpredetermined speeds via a fan switch. Each Peltier module can bemanually adjusted to operate in various heating or cooling modes via atemperature switch. The electrical power to each Peltier is pulsed at aduty cycle corresponding to a particular heating or cooling mode ofoperation to optimize electrical efficiency. Each heat pump may beoperated independently via separate fan and temperature switches, or maybe operated simultaneously by a common fan and temperature switch.Alternatively, each heat pump may be operated automatically by thecontroller when the variable temperature seat is occupied by theactivation of an occupant presence switch.

After an initial fan speed and Peltier temperature setting has beenselected, the controller monitors the temperature information relayedfrom each heat pump. In addition, the controller may also be configuredto monitor the ambient temperature of the air surrounding the variabletemperature seat occupant as well as the temperature of the conditionedair directed to the variable temperature seat occupant, via the use ofadditional temperature sensors. The controller regulates the operationof each main exchanger fan, each waste exchanger fan, and each Peltiermodule according to a temperature climate control algorithm. The controlalgorithm is designed to maximize occupant comfort and minimize thepossibility of equipment damage, occupant discomfort or even occupantinjury in the event of a system malfunction.

The control algorithm is designed to interrupt or limit the power to thePeltier modules and/or each main exchanger fan in the event that theheat pump temperature exceeds a predetermined maximum temperature or apredetermined minimum temperature, indicating a possible heat pumpmalfunction. Additionally, the control algorithm is designed tointerrupt power to the Peltier modules in the event that the temperatureof the conditioned air directed to the variable temperature seatoccupant exceeds a predetermined maximum or minimum temperature.

The control algorithm is also designed to limit the power to the Peltiermodules during the cooling mode of operation when the temperature of thecooling air directed to the occupant exceeds a predetermined minimumcooling temperature and the temperature has not been adjusted for apredetermined period of time, thus minimizing possible occupantdiscomfort associated with overcooling the occupant's back. In addition,the control algorithm is designed to limit the power to the Peltiermodules during the cooling mode of operation when the temperaturedifference between the ambient air surrounding the variable temperatureseat occupant and the conditioned air directed to the occupant isgreater than a predetermined amount.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention willbecome appreciated as the same becomes better understood with referenceto the specification, claims and drawings wherein:

FIG. 1 is a cross-sectional semi-schematic view of an embodiment of avariable temperature seat;

FIG. 2 is a schematic view of a first embodiment of the temperatureclimate control system according to the present invention;

FIG. 3 is a flow chart illustrating a temperature climate controlalgorithm for the embodiment of the invention shown in FIG. 2;

FIG. 4 is a schematic view of a second embodiment of the temperatureclimate control system according to the present invention;

FIG. 5 is a flow chart illustrating a temperature climate controlalgorithm for the embodiment of the invention shown in FIG. 4;

FIG. 6 is a schematic view of a third embodiment of the temperaturecontrol climate control system according to the present invention;

FIG. 7 is a flow chart illustrating a temperature climate controlalgorithm for the embodiment of the invention shown in FIG. 6; and

FIG. 8 is a schematic view of an alternative embodiment of thetemperature climate control system according to the present invention.

DETAILED DESCRIPTION

A temperature climate control system (TCCS) provided in the practice ofthis invention may be used to control the temperature of air beingdistributed through a variable temperature seat (VTS) and directed to aseated occupant. The TCCS may be used in various VTS applications whereit is required that an occupant stay seated for a period of time, suchas automobiles, trains, planes, buses, dentists chairs, hair stylingchairs and the like, or where an occupant simply desires an added degreeof comfort while he/she is sitting at work or in the home, such asoffice chairs, home recliners and the like. The TCCS configuredaccording to the practice of this invention to operate in a mannerproviding an occupant seated in a VTS a maximum degree of comfort byallowing the occupant to manually adjust both the flow rate and thetemperature of the air being passed through the seat surface anddirected to the occupant.

The TCCS is configured to automatically override the manual flow rateand temperature settings when it senses that the temperature of the airbeing directed to the occupant is above a predetermined maximumtemperature set point or is below a predetermined minimum temperatureset point. Thus, maximizing both occupant comfort and occupant safety inthe event that the occupant either falls asleep or in the event that thedevice generating the temperature conditioned air malfunctions. The TCCSalso comprises timers and is configured to automatically override themanual flow rate and temperature settings during normal operation toprevent back discomfort. Additionally, the device generating thetemperature conditioned air is operated in a manner maximizingelectrical efficiency, making it well suited for use in applicationsthat are sensitive to electrical consumption, such as electric poweredvehicles.

FIG. 1 shows an embodiment of a VTS 10 comprising a seat back 12 and aseat bottom 14 for accommodating the support of a human occupant in thesitting position. FIG. 1 shows a simplified cross-sectional view of aVTS for purposes of illustration and clarity. Accordingly, it is to beunderstood that the VTS may be constructed in embodiments other thanthat specifically represented. The VTS may be constructed having aoutside surface covering 16 made from a suitable material that allowsthe flow of air through its surface, such as perforated vinyl, cloth,leather or the like. A padding layer 17 such as reticulated foam may liebeneath the outside surface 16 to increase occupant comfort.

The VTS may be constructed having a metal frame (not shown) thatgenerally defines the seat configuration and having seat bottom and seatback cushions 18 made from foam and the like. A number of air channels20 are positioned within each seat cushion and extend from the paddinglayer 17 through the seat cushions and to either a seat bottom air inlet22 or a seat back air inlet 24. Although a particular embodiment of aVTS has specifically described, it has to be understood that the TCCSaccording to the present invention is meant to operate with any type ofVTS having the same general features.

FIG. 2 shows a first embodiment of the TCCS according to the presentinvention comprising a VTS 10. The air that is passed through the seatand to the occupant is temperature conditioned by a heat pump. Thisfirst embodiment comprises a seat back heat pump 26 for temperatureconditioning the air passed through the seat back 12 of the VTS, and aseat bottom heat pump 28 for temperature conditioning the air passedthrough the seat bottom 14 of the VTS. The seat back heat pump and seatbottom heat pump each comprise at least one thermoelectric device 30 and32, respectively, for temperature conditioning, i.e., selectivelyheating or cooling, the air. A preferred thermoelectric device is aPeltier thermoelectric module. Each heat pump may comprise more than onePeltier thermoelectric module. A preferred heat pump comprisesapproximately three Peltier thermoelectric modules.

Each heat pump comprises a main heat exchanger 34 and 36, enclosing airtemperature conditioning fins (not shown) depending from one surface ofthe Peltier modules, and a waste heat exchanger 39 and 40, enclosingthermal exchanger fins (not shown) extending from the Peltier modulesurface opposite the main heat exchanger. Attached to one end of eachmain heat exchanger is an outlet from a main exchanger fan 42 and 44that serves to pass the temperature conditioned air in each main heatexchanger to the seat back or seat bottom, respectively. Each mainexchanger fan may comprise an electrical fan having a suitable flowrate, such as an axial blower and the like. The outlet end of each mainheat exchanger is connected to an air conduit 46 and 48 that isconnected to the respective seat back air inlet 24 or seat bottom airinlet 22. Accordingly, the temperature conditioned air produced by thePeltier thermoelectric modules in each main heat exchanger is passedthrough the respective air conduit, through the respective air inlet,into and through the respective seat portion of the VTS to the occupantby the main exchanger fan.

Attached to one end of each waste heat exchanger is an outlet from awaste exchanger fan 50 and 52 that serves to pass unwanted waste heat orcooling produced in each waste heat exchanger to the outside environmentsurrounding the VTS. Each waste exchanger fan may comprise an electricalfan having a suitable air flow rate, such as an axial blower and thelike. The waste air exiting each waste heat exchanger fan is usually atan undesirable temperature, i.e., in the cooling mode it is hot air andin the heating mode it is cold air. Consequently, waste air exiting eachwaste exchanger may be specifically routed away from any occupant,possibly through the sides of the seat or the like.

Attached to the main exchanger side of the Peltier thermoelectricmodules in each heat pump is a temperature sensor 54 and 56. Eachtemperature sensor may comprise an electric thermocouple and the like.

The operation of the main exchanger fans 42 and 44 can be manuallycontrolled by a fan switch 58. In the first embodiment, it is preferredthat the main exchanger fans are operated simultaneously by a single fanswitch. The fan switch may comprise an electrical switch configured toprovide an off position, and a variety of fan speed settings if desired.It is preferred that the fan switch be configured having an off positionand three different fan speed settings, namely low, medium and high. Thefan switch may be located within or near the VTS for easy occupantaccess.

The operation of the waste exchanger fans 50 and 52 can be manuallycontrolled by a separate fan switch (not shown) if desired. However, itis preferred that the waste exchanger fans be activated automaticallyupon the operation of the main exchanger fans and operate at a singlepredetermined speed. Accordingly, upon the manual operation of the fanswitch 58, both the main exchanger fans are activated to a selectedspeed and the waste exchanger fans are automatically activated tooperate at maximum speed. Configuring the TCCS to operate in this mannermaximizes the thermal efficiency of the Peltier modules and reduces thepossibility of system damage.

The operation of the Pelter thermoelectric modules can be controlled bya temperature switch 60. In the first embodiment it is preferred thatthe Peltier thermoelectric modules in both heat pumps be operatedsimultaneously by a single temperature switch. The temperature switchmay comprise an electrical switch configured to provide an off position,and a variety of temperature settings if desired. A preferred fan switchis configured having an off position, four heating positions, and fourcooling positions. Like the fan switch 58, the temperature switch 60 maybe located within or near the VTS for easy occupant access.

When the temperature switch is turned to one of the cooling positions aLED lamp 62 located near the temperature switch registers a green color,indicating that the Peltier modules are operating in the cooling mode.When the temperature switch is turned to one of the heating positionsthe LED lamp registers a red color, indicating the Peltier modules areoperating in the heating mode.

The different heating or cooling modes for the Peltier modules isaccomplished by both switching the polarity and limiting the amount ofthe electrical power routed to the Peltier modules. To optimize theelectrical efficiency of the Peltier modules, instead of using apotentiometer to discharge the unwanted portion of the electrical powerthrough a resister, the four different modes of heating and coolingoperation are achieved by pulsing electrical power to the Peltiermodules at predetermined duty cycles. Accordingly, the different levelsof heating or cooling are accomplished by pulsing the electrical powerto the Peltier modules at a predetermined duty cycle. In a preferredembodiment, the duty cycle is about 0.02 seconds (50 hz) and the fourdifferent levels are accomplished by applying either 25 percent, 50percent, 75 percent, or 100 percent of the cycle time power. In thisembodiment, a 25 percent duty cycle would be on for approximately 0.005seconds and off for approximately 0.015 seconds for a total cycle lengthof 0.02 seconds, and then repeated. The 75 percent duty cycle is on forapproximately 0.015 seconds and off for approximately 0.005 seconds.

The heating or cooling mode of the Peltier modules is achieved byswitching the polarity of the electrical power. The Peltier modules areconfigured to operate in the heating mode on approximately ten volts DCand in the cooling mode on approximately six volts DC. A DC convertermay be positioned outside the controls to supply the heating and coolingvoltage. The total duty cycle of the Peltier modules is adjustable from0.02 to 0.2 seconds. The power for the Peltier modules in each mode waschosen to optimize the efficiency and total thermal power supplied to anoccupant of the VTS.

The electrical feeds to and/or outlets from the fan switch 58,temperature switch 60, main exchanger fans 42 and 44, waste exchangerfans 50 and 52, Peltier thermoelectric modules 30 and 32 LED lamp 62,and temperature sensors 54 and 56 and routed to a controller 64.Alternatively, the electrical feeds ad signals may first be routed to aprinted circuit board in the seat (not shown) that sends a signal to thecontroller. The controller comprises a power inlet 66 of sufficientelectrical capacity to operate all of the aforementioned devices. Thecontroller is configured to receive occupant inputs from the fan switchand the temperature switch and temperature information from thetemperature sensors. From this input the controller is configured tomake adjustments to the operation of the heat pumps according to apredetermined algorithm designed to ensure occupant comfort and safety,and protect against system damage.

FIG. 3 is a flow chart illustrating a temperature climate controlalgorithm for the first embodiment of the TCCS shown in FIG. 2. Theoccupant wishing to use the VTS operates the main exchanger fans byactivating the fan switch 58 and selecting a desired fan speed (step68). Upon the activation of the main exchanger fans the waste exchangerfans are also activated to operate at a maximum speed (step 70).

The occupant may activate the Peltier modules for temperatureconditioning the air in the VTS by positioning the temperatures witch 60to a desired heating or cooling mode (steps 72 and 74). The Peltiermodules can be manually deactivated by selecting the “off” position onthe temperature control switch, in which case the power to the fans ismaintained as indicated by the LED 62 registering a green color (step76). Additionally, the Peltier modules are automatically deactivated bythe controller when the fan switch is manually placed in the “off”position (step 78).

When the temperature switch is positioned to one of the four coolingmodes the LED lamp 62 registers a green color (step 80). The temperaturedetected by the temperature sensors 54 and 56 in both heat pumps 26 and28 is passed to the controller (step 82). If the temperature is belowabout 303° K. (step 84) the power to the Peltier modules remains on(step 86), unless more than six minutes has elapsed since the time thatthe occupant has last adjusted the temperature (step 88), in which casethe power to the Peltier modules is reduced to 25 percent (step 90). Itis desirable to reduce the power to the Peltier modules under suchcircumstances to prevent over cooling of the occupant's back, which hasbeen shown to cause the occupant discomfort after use of the VTS. If thetemperature is not below 303° K., however, the power to the Peltiermodules is maintained as indicated by the occupant controls (step 86).

When the temperature switch is positioned to one of the four heatingmodes the LED lamp 62 registers a red color (step 92). If thetemperature is below about 339° K. (step 94) the power to the Peltiermodules remains on (step 96). If the temperature is in the range of from339° K. to 349° K. (step 92) the power to the Peltier modules is reducedto 25 percent until the temperature is below 339° K. (step 98). Reducingthe power to the Peltier modules in this situation is desired to preventthe Peltier modules from overheating.

If the temperature of the main heat exchanger side of the Peltiermodules is below either below 200° K. or above 349° K. (step 100),regardless of whether the Peltier modules are in the heating or coolingmode, the controller deactivates the Peltier modules (step 76) andmaintains the operation of the main exchanger fans and waste exchangerfans. The occurrence of either of the above temperature conditionsindicates a system malfunction. In this condition the LED lamp 62registers a orange color, indicating a system malfunction.

The first embodiment comprises conditioned air temperature sensors 102and 104 positioned in the air flow of the temperature conditioned airpassing to the seat, back and seat bottom, respectively, as shown inFIG. 2. The conditioned air temperature sensors are electricallyconnected to the controller 64. The temperature climate controlalgorithm described above and illustrated in FIG. 3 is configured todeactivate the Peltier modules in the event that the temperature of theconditioned air is greater than about 325° K. or below about 297° K.While the Peltier modules are deactivated the main exchanger fanscontinue to run.

FIG. 4 shows a second embodiment of the TCCS according to the practiceof the present invention. The second embodiment is similar to the firstembodiment in all respects, except for the addition of at least oneambient air temperature sensor 102 to monitor the temperature of the airoutside of the VTS surrounding the occupant. The temperature sensor iselectrically connected to relay ambient air temperature information tothe controller 64. More than one ambient air temperature sensor may beused, each being positioned at different locations in the environmentsurrounding the occupant, to provide an ambient air temperature profileto the controller.

The second embodiment of the TCCS also differs from the first preferredembodiment in that the fan speed and air temperature for the seat backheat pump 26 and the seat bottom heat pump 28 can each be manuallyadjusted independently by using a separate seat back fan switch 104 andseat bottom fan switch 106, and a separate seat back temperature switch108 and seat bottom temperature switch 110. The fan switches 104 and 106and the temperature switches 108 and 110 in the second embodiment arethe same as those previously described in the first embodiment.Alternatively, the TCCS may be configured having a single fan switch(not shown) to control the speed of fans 42 and 44 and two temperatureswitches (not shown) to control the power to each heap pump 26 and 28independently. The TCCS may also be configured having a singletemperature switch (not shown) to control the power of heat pumps 26 and28 simultaneously and two fan switches to control the speed of each fan42 and 44 independently.

LED lamps 112 and 114 are located near each temperature switch toindicate the mode of operation selected for each heat pump, e.g., in theoff position the LED lamps are off, when both heat pumps are in thecooling mode the LED lamps register a green color, when both heat pumpsare in the heating mode the LED lamps register a red color, when thereis a temperature error or Peltier module malfunction in either heat pumpthe LED lamps fast cycle red and green, registering an orange color.

Configuring the manual fan speed and temperature switches in this mannerallows the occupant the ability to operate the seat back 12 of the VTSat a different conditions than the seat bottom 14. This may be desirablewhere a medical condition or injury requires that a particular portionof the occupant's body be maintained at a temperature different from theremaining portion of the occupant, e.g., where a leg injury requirescooling air in the seat bottom of the VTS and the ambient temperaturedictates that heated air pass through the seat back for maximum occupantcomfort.

Like the first embodiment, the electrical feeds to and/or outlets fromthe fan switches 104 and 106, temperature switches 108 and 110, mainexchanger fans 42 and 44, waste exchanger fans 50 and 52, Peltierthermoelectric modules 30 and 32, temperature sensors 54 and 56, LEDlamps 112 and 114, and the ambient air temperature sensor 102 are routedto the controller 64.

FIG. 5 is a flow chart illustrating a temperature climate controlalgorithm for the second embodiment of the TCCS shown in FIG. 4. Thecontrol algorithm is similar to that previously described above andshown in FIG. 3, except for the additional temperature inputs from theambient temperature sensor (step 116) and the conditioned air sensor,and except when the Peltier modules are being operated in the coolingmode and the temperature of the conditioned air from the seat back heatpump 26 is below about 310° K. (step 119). When the conditioned airtemperature is below about 310° K., if it has been greater than sixminutes since the last temperature adjustment by the occupant (step120), and the conditioned air temperature of the conditioned isapproximately 3° K. or more below the temperature of the ambient airsurrounding the occupant (step 122) , the controller reduces the powerto the Peltier modules in the seat back heat pump 26 to approximately 25percent (step 124). If the temperature is below about 310° K., but ithas either been less than six minutes since the last manual temperatureadjustment or the conditioned air temperature is less than 3° K. belowthe ambient temperature, the power to the Peltier modules in the seatback heat pump remains on at the occupant controlled setting (step 126).

Like the control algorithm described in FIG. 3, the reason for reducingthe power to the Peltier modules under such conditions is to regulatethe amount of cooling air directed to an occupant's back to preventpossible discomfort after using the VTS.

The second embodiment also comprises conditioned air temperature sensors128 and 130 positioned in the air flow of the temperature conditionedair passing to the seat, back and bottom, respectively, as shown in FIG.4. The conditioned air temperature sensors are electrically connected tothe controller 64. The temperature climate control algorithm describedabove and illustrated in FIG. 5 is configured to deactivate the Peltiermodules in the event that the temperature of the conditioned airdirected to the occupant is greater than about 325° K. or below about297° K. While the Peltier modules are deactivated the main exchangerfans continue to run.

FIG. 6 shows a third embodiment of the TCCS according to the practice ofthis invention. The third embodiment is similar to the first embodimentin all respects except for two. One is the addition of at least oneambient air temperature sensor 132 to monitor the temperature of the airoutside of the VTS surrounding the occupant. The temperature sensor iselectrically connected to feed temperature information to the controller64. More than one ambient air temperature sensor may be used, each beingpositioned at different locations in the environment surrounding theoccupant, to provide an ambient air temperature profile to thecontroller.

The second difference in the third embodiment of the TCCS is that only asingle heat pump 134 is used to provide temperature conditioned air toboth the seat back 12 and the seat bottom 14. The single heat pump issimilar to the seat back heat pump 26 and seat bottom heat pump 28previously described in the first embodiment in that it comprises a mainheat exchanger 136, a main exchanger fan 138, a waste heat exchanger140, a waste exchanger fan 142 and a Peltier module temperature sensor143. However, instead of three Peltier thermoelectric modules, thesingle heat pump 134 comprises four Peltier thermoelectric modules 144.The temperature conditioned air from the main heat exchanger is passedto the seat back 12 and seat bottom 14 of the VTS by an air manifold 146connected at one end to the outlet of the main heat exchanger 136 and atthe other end to the seat back air inlet 24 and seat bottom air inlet22. Alternatively, the third embodiment of the TCCS may comprise adouble heat pump arrangement similar to that previously described in thefirst embodiment.

The third embodiment of the TCCS also differs from the first embodimentin that the main exchanger fan speed and the heat pump air temperatureare not manually adjustable by the occupant. Rather, the fan speed andthe air temperature are controlled automatically by the controller 64.Additionally, an occupant presence switch 148 is located within the VTSthat is activated upon the presence of an occupant in the seat. Theoccupant presence switch may comprise a weight sensitive switch and thelike located in the seat back or seat bottom. In a preferred embodiment,the occupant presence switch is located in the seat bottom and iselectrically connected to the controller to relay the presence of anoccupant. The use of a occupant presence switch to control theactivation of the VTS is desired for purposes of conserving electricitywhen the VTS is not occupied and when it is not practical or desirableto give individual control over the seats, e.g., in bus passengerseating applications.

FIG. 7 is a flow chart illustrating a temperature climate controlalgorithm for the third embodiment of the TCCS as shown in FIG. 6. Theactivation of the main exchanger fan 138 is controlled by an occupantsitting in the VTS (step 150), which activates the occupant presenceswitch, and the ambient conditions inside the vehicle as transmitted tothe controller by the ambient temperature sensors (step 148). To ensurea rapid temperature response upon placement of an occupant in the VTS,the controller pulses electrical power to the Peltier modules in theabsence of an occupant at a steady state of voltage in the range of from0.5 to 1 volt (step 152). The voltage that is actually applied duringthe duty cycle may be six or twelve volts. By maintaining a slowcontinuous pulse of power to the Peltier modules the transient time forachieving the desired temperature of conditioned air upon the presenceof an occupant in the VTS is greatly minimized.

Once an occupant is seated in the VTS, the particular main fan speed andPeltier operating mode selected by the controller is dependent upon theambient temperature surrounding the VTS occupant. When the ambienttemperature is less than about 286° K. (step 154) the controller selectsa heating mode of operation and passes 100 percent power to the Peltiermodules and operates the main exchanger fan at medium speed (step 156).Upon the activation of the main exchanger fan the waste exchanger fan isalso activated at high speed.

When the ambient temperature is between 286° K. and 290° K. (step 158)the controller selects a heating mode of operation and passes 75 percentpower to the Peltier modules and operates the main exchanger fan atmedium speed (step 160). When the temperature is between 290° K. and293° K. (step 162) the controller selects a heating mode of operationand passes 25 percent power to the Peltier modules and operates the mainexchanger fan at a medium speed (step 164).

When the ambient temperature is between 293° K. and 297° K. the (step166) the controller pulses power to the Peltier modules at a steadystate of approximately 0.5 volts and deactivates the main exchanger fan(step 168).

When the ambient temperature is between 297° K. and 297° K. (step 170)the controller selects a cooling mode of operation and passes 50 percentpower to the Peltier modules and operates the main exchanger fan atmedium speed (step 172). When the ambient temperature is between 300° K.and 302° K. (step 174) the controller selects a cooling mode ofoperation and passes 50 percent power to the Peltier modules andoperates the main exchanger fan at high speed (step 176). When theambient temperature is above 302° K. (step 178) the controller selects acooling mode of operation and passes 100 percent power to the Peltiermodules and operates the main exchanger fan at high sped (step 180).

In either the heating mode of operation (ambient temperatures up to 293°K.) or the cooling mode of operation (ambient temperatures above 297°K.), a Peltier modules temperature (step 182) below 200° K. or above394° K. (step 184) causes the controller to deactivate the Peltiermodules and maintain the operation of the main exchanger fan and wasteexchanger fan (Step 186). Either of the above conditions indicate asystem malfunction.

The third embodiment also includes a conditioned air temperature sensor188 positioned in the air flow of the temperature conditioned airpassing to the seat, as shown in FIG. 6. The conditioned air temperaturesensor is electrically connected to the controller 64. The temperatureclimate control algorithm described above and illustrated in FIG. 7 isconfigured to deactivate the Peltier modules 144 in the event that thetemperature of the conditioned air passing to the seat and to theoccupant is greater than about 325° K. or below about 297° K. While thePeltier modules are deactivated the main exchanger fans continue to run.

The third embodiment of the TCCS as specifically described above andillustrated in FIG. 6 is used for controlling multiple VTSs inmulti-occupant applications such as buses, trains, planes and the like.In such an application the main exchanger fan, waste exchanger fan,Peltier modules, temperature sensor, and weight sensitive switch fromeach VTS are electrically connected to a common controller. Multipleambient air temperature sensors may be placed at different locationswithin the vehicle to provide an accurate temperature profile throughoutthe interior of the vehicle. The common controller is configured toaccommodate inputs from the multiple ambient air temperature sensors.The common controller may be configured to control the main fan speedand mode of operation for the Peltier modules in the same manner as thatspecifically described above and illustrated in FIG. 7, taking intoaccount the possibility of different ambient temperature zones withinthe vehicle surrounding each VTS.

Although limited embodiments of the temperature climate control systemhave been described and illustrated herein, many modifications andvariations will be apparent to those skilled in the art. For example, itis to be understood within the scope of this invention that atemperature climate control system according to the present inventionmay comprise means for automatically adjusting the flow of temperatureconditioned air from a single heat pump to the seat back or the seatbottom.

FIG. 8 illustrates an alternative embodiment of the third embodiment ofthe TCCS, incorporating the use of valves 190 and 192 placed in the airmanifold 146 leading to the seat back and the seat bottom, respectively.The valves are activated electrically by a controller 64 according to apredetermined control algorithm. The control algorithm may be the sameas that specifically described above and illustrated in FIG. 7 for thethird embodiment, with the addition that controller limits the flow ofcooling air to the seat back by closing valve 190 in the event that theoccupant receives too much cooling air over a period of time. Thisembodiment would help eliminate the occurrence of occupant discomfortafter using the VTS.

In addition to the embodiments of the TCCS specifically described andillustrated, it is to be understood that such the TCCS may incorporateinput from an energy management system, such as that used in electricpowered vehicles. In specific embodiments, the TCCS is configured toaccept an inhibit signal from such an energy management system. Theinhibit signal is typically activated by a vehicle's energy managementsystem under particular conditions of operation when an additionalamount of energy is required or when the battery is being discharged torapidly, such as during hard acceleration, when climbing a hill, or whenthe battery is weak or is approaching its minimum discharge voltage. Thetemperature climate control algorithm according to the present inventioncan be configured to deactivate the Peltier modules, the main exchangerfans, and the waste exchanger fans upon activation of the inhibitsignal.

Accordingly, it is to be understood that, within the scope of theappended claims, the temperature climate control system according toprinciples of this invention may be embodied other than as specificallydescribed herein.

What is claimed is:
 1. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having means for distributing temperature conditioned air through the seat to increase a seat occupant's thermal comfort; at least one heat pump connected to the seat by an air conduit for providing temperature conditioning conditioned air to the seat, the heat pump comprising: at least one thermoelectric module for temperature conditioning the air ; at least one fan for passing the temperature conditioned air through the seat to an occupant and for removing unwanted thermal energy from the thermoelectric module to the seat; a controller for activating and regulating the operation of the thermoelectric module and fan of at least one heat pump independent of occupant input after a desired mode of operation has been selected; means for automatically operating the controller to optimize change system response, to provide maximum thermal comfort to the seated occupant, and to control cooling functions of the system to minimize reduce occupant discomfort and adverse physiological response; and an indicator switch attached to the seat to detect the presence of an occupant, the indicator switch being electrically connected to the controller.
 2. The system as recited in claim 1, comprising a temperature sensor attached to the heat pump to sense the operation of the heat pump, the temperature sensor being electrically connected to the controller to facilitate controlling the operation of the heat pump. with at least one of a sensor sensing the temperature of the heat pump, a sensor sensing the temperature of the seat, or a sensor sensing the ambient air temperature near the seat.
 3. The system as recited in claim 2 1, comprisingwherein the sensor comprises at least one temperature sensor positioned in the flow path of the temperature conditioned airfluid.
 4. The system as recited in claim 1, comprising more than one seat, the operation of each heat pump for each seat being automatically regulated by a single controller capable of providing different comfort control to different seats.
 5. A method for controlling the temperature climate in a variable temperature occupant seat, the method comprising the steps of: activating at least one thermoelectric module to provide temperature conditioned air to be distributed through a variable temperature seat ; activating at least one electric fan for passing the temperature conditioned air through means inside of to the variable temperature seat; sensing a system temperature and relaying the temperature information to a controller; automatically adjusting the electrical power to the thermoelectric module when the thermoelectric module is operated in a cooling mode and when the temperature of the temperature conditioned air is below a minimum cooling temperature a predetermined amount of time after the cooling mode has been selected; and automatically activating each fan and each thermoelectric module by occupying the seat and automatically deactivating each fan and the thermoelectric module by vacating the seat.
 6. The method as recited in claim 5, comprising manually adjusting the speed of each electric fan and mode of operation for each thermoelectric module to provide a desired flow rate and temperature of conditioned air directed to the occupant.
 7. A method for controlling the temperature climate in a variable temperature occupant seat, the method comprising the steps of: sensing whether the seat is occupied and relaying the information to a controller configured to automatically regulate the operation of one or more thermoelectric modules and fans; activating at least one thermoelectric module in response to sensing occupancy of the seat to provide temperature conditioned air; activating at least one fan for passing to pass the temperature conditioned air through air channels inside of to the variable temperature seat; sensing a system temperature and relaying the temperature information to the controller; and automatically reducing electrical power to the thermoelectric modules when operated in a cooling mode after the temperature of the temperature conditioned air is below a minimum cooling temperature and after a maximum amount of time has passed since the system was placed in a cooling mode of operation.
 8. The method as recited in claim 7, further comprising the steps of reducing electrical power to the thermoelectric modules when operated in a cooling mode, the operating temperature is below a predetermined cooling temperature, a predetermined amount of time has passed since the temperature was last adjusted by the occupant, and the temperature of the conditioned air directed to an occupant is a cooler by a predetermined amount than the ambient temperature surrounding the occupant wherein the step of automatically changing the electrical power comprises the step of changing the power based on signals correlated to temperature and to elapsed time.
 9. A method for controlling the temperature climate in a variable controlled occupant seat, the method comprising the steps of: activating a number of thermoelectric modules for temperature conditioning air to be passed and distributed through a variable temperature seat to generate temperature conditioned air; activating at least one fan for passing the temperature conditioned air through air channels inside of the variable temperature seat to an occupantcommunicating the temperature conditioned air to the occupant seat by at least one fan; and; sensing the a control temperature of the thermoelectric modules and relaying information correlated to the temperature information to a controller configured to automatically deactivate the operation of the thermoelectric modules and fans the at least one fan when the temperature is below approximately 200° K. and above approximately 349° K.; automatically decreasing the electrical power to the thermoelectric modules when the thermoelectric modules are operated in a cooling mode, the temperature is below approximately 303° K., and it has been more than 6 minutes since the operating mode was last adjusted by the occupant; and automatically decreasing the electrical power to the thermoelectric modules when the thermoelectric modules are operated in a heating mode and the temperature is in the range of from 339° K. to 349° K reaches a predetermined limit for a predetermined time to prevent damage to one of the occupant seat or a seat occupant.
 10. The method as recited in claim 9, comprising sensing wherein the control temperature comprises at least one of the temperature of the conditioned air directed to the occupant and the temperature of the ambient air surrounding the occupant and relaying the temperature information to the controller .
 11. The method as recited in claim 10, comprising automatically decreasing changing the electrical power to the thermoelectric modules when the thermoelectric modules are operated in a cooling mode, the temperature is below approximately 303° K., it has been more than 6 minutes since a the operating mode was last adjusted by the occupant, and the temperature of the conditioned air is more than 3° K. less than the temperature of the ambient air .
 12. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having means at least one conduit configured to distribute a sufficient amount of temperature conditioned air through the seat and the temperature conditioned air through the seat for the purpose of increasing to increase a seat occupant's thermal comfort; at least one heat pump for providing temperature conditioned air, each heat pump being connected to in fluid communication with the conduit in the seat by an air conduit and including one or more fans and one or more thermoelectric modules; a controller for activating and regulating the operation of each in electrical communication with the heat pump to produce and fan and controlled to provide temperature conditioned air at a temperature and fan speed to maximize to increase the thermal comfort of the a seated occupant; at least one temperature sensor for monitoring the operation of at least one heat pump, the temperature sensor being electrically connected to the controller or monitoring the temperature of the air passing through the heat pump, or monitoring ambient air temperature and providing a signal correlated to that operation or monitored temperature to the controller; means for automatically operating the controller to optimize system response, to provide maximum thermal comfort to the seated occupant, and to control heating and cooling functions of the system to minimize reduce occupant discomfort and adverse physiological response; and an indicator for detecting the presence of the seat occupant, the indicator being electrically connected to the controller.
 13. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having means at least one distribution conduit configured to distribute temperature conditioned air through the seat and the temperature conditioned air through the seat for the purpose of increasing to increase a seat occupant's thermal comfort; at least one heat pump for providing temperature conditioned air from the heat pump to the distribution conduit, each heat pump being connected to the seat by an air conduit and including one or more fans and one or more thermoelectric modules; a controller for activating and regulating the operation of each heat pump to produce temperature conditioned air at a temperature and fan speed to maximize adjust the thermal comfort of the seated occupant; at least one temperature sensor for monitoring the operation of at least one heat pump, the temperature sensor being electrically connected to the controller; and means for automatically operating the controller to optimize vary the system response, to provide maximum thermal comfort to the seated occupant, and to control heating and cooling functions of the system, to minimize reduce occupant discomfort and adverse physiological response, wherein the means for automatically operating the controller reduces the cooling functions of the system when the temperature of the temperature conditioned air is below a minimum cooling temperature and after a maximum amount of time has passed since the system was placed in a cooling mode of operation.
 14. The system as recited in claim 13, wherein the reduction in cooling functions variation in temperature conditioned air is achieved by reducing power changing voltage to the thermoelectric module.
 15. The system as recited in claim 13, wherein the reduction in cooling functions variation in temperature conditioned air is achieved by reducing changing power to at least one of the thermoelectric module and to the fan.
 16. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having means for distributing temperature conditioned air through the seat to increase a seat occupant's thermal comfort; at least one heat pump connected to the seat by an air conduit for providing temperature conditioning air to the seat, each heat pump comprising: ; at least one thermoelectric module for temperature conditioning the air; at least one fan for passing positioned to move the temperature conditioned air through the seat to an occupant and for removing unwanted thermal energy from the thermoelectric module conduit; a controller for activating and regulating the operation of the thermoelectric module and fans of each heat pump independent of occupant input after a desired mode of operation has been selected; means for automatically operating the controller to optimize system response, to provide maximum thermal comfort to the seated occupant, and to control heating and cooling functions of the system, to minimize reduce occupant discomfort and adverse physiological response, wherein the means for automatically operating the controller reduces the cooling functions of the system when the temperature of the temperature conditioned air is below a minimum cooling temperature and after a maximum amount of time has passed since the system was placed in a cooling mode of operation.
 17. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat comprising a seat bottom and a seat back portion each having means for distributing an air distribution conduit sized and located to distribute temperature conditioned air through the seat and directing it to an occupant; a seat back heat pump for conditioning the temperature of the air and passing the air through an air conduit to the seat back, the seat back heat pump comprising a main exchanger fan and at least one thermoelectric module ; a seat bottom heat pump for conditioning the temperature of the air and passing the air through an air conduit to the seat bottom, the seat bottom heat pump comprising a main exchanger fan and at least one thermoelectric module ; at least one fan arranged to move air from at least one of the heat pumps through the air conduit associated with the respective heat pump; aat least one temperature sensor positioned in each heat pumpto monitor the temperature of at least one of the ambient air, conditioned air from at least one heat pump, or at least one heat pump; a controller for automatically activating and regulating the speed of the main fans, and automatically selecting the mode of operation for the thermoelectric module in each heat pump receiving information from the temperature sensor and configured to automatically activate and regulate at least one of the speed of the fans and the temperature of the air conditioned by at least one of the heat pumps; means for automatically operating the controller to optimize system response, to provide maximum thermal comfort to the seated occupant, and to control cooling functions of the system to minimize occupant discomfort and adverse physiological response, wherein the means for automatically operating the controller reduces the cooling functions of the system when the temperature of the temperature conditioned air is below a minimum cooling temperature and after a maximum amount of time has passed since the system was placed in a cooling mode of operation.
 18. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat comprising a seat bottom and a seat back portion each having means for distributing a system configured and located to distribute temperature conditioned air through in the seat and directing it to an occupant ; a seat back heat pump for conditioning the temperature of the air and passing the air through an air conduit to the seat back, the seat back heat pump comprising a main exchanger fan and at least one thermoelectric module in fluid communication with a fan arranged to pass temperature conditioned air to the system; aat least one seat bottom heat pump for conditioning the temperature of the air and passing the air through an air conduit to the seat bottom, the seat bottom heat pump comprising a main exchanger fan and at least one thermoelectric modulein fluid communication with a fan arranged to pass temperature conditioned air to the system; aat least one temperature sensor positioned in each heat pumpto monitor the temperature of at least one of the seat bottom, seat back, ambient air, conditioned air from at least one heat pump, and at least one heat pump; a controller for automatically activating and regulating the speed of the main fans, and automatically selecting the mode of operation for the thermoelectric module in each heat pump receiving information from the temperature sensor and configured to automatically activate and regulate at least one of the speed of the fans and the temperature of the air conditioned by at least one of the heat pumps; means for automatically operating the controller to optimize system response, to provide maximum thermal comfort to the seated occupant, and to control cooling functions of the system to minimize occupant discomfort and adverse physiological response; and an indicator for detecting the present of an occupant, the indicator being electrically connected to the automatic operating means controller.
 19. A system as defined in claim 16, wherein the time and power to the controller vary with a temperature signal from the least one temperature sensor.
 20. A system as defined in claim 17, wherein the time and power to the controller vary with a temperature signal from the least one temperature sensor.
 21. A system as defined in claim 9, further comprising the step of automatically changing the electrical power to the thermoelectric modules when the control temperature reaches a predetermined temperature and/or when a predetermined amount of time has passed.
 22. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having a conduit to distribute temperature conditioned heating or cooling medium to an area of a seat; at least one heat pump connected to the seat by a conduit for providing a temperature conditioning medium to the conduit in the seat; at least one fan for passing the temperature conditioned air to the conduit in the seat; a controller for activating and regulating the operation of the fan independent of occupant input after a desired mode of operation has been selected; means for automatically operating the controller to change system response, to provide thermal comfort to the seated occupant, and to control cooling functions of the system to reduce occupant discomfort and adverse physiological response; and an indicator switch located within the seat to detect the presence of an occupant, the indicator switch being electrically connected to the controller.
 23. A method for controlling the temperature climate in a variable temperature occupant seat, the method comprising the steps of: activating at least one thermoelectric module to provide temperature conditioned air; activating at least one electric fan for passing the temperature conditioned air to the variable temperature seat; sensing a system temperature and relating the temperature information to a controller; automatically adjusting the electrical power to the thermoelectric module based upon temperature and elapsed time information to adjust the temperature of the air distributed to the occupant seat; and automatically activating each fan and each thermoelectric module by occupying the seat and activating a weight-sensitive sensor and automatically deactivating each fan and the thermoelectric module by vacating the seat and deactivating a weight-sensitive sensor.
 24. A method for controlling the temperature climate in a variable temperature occupant seat, the method comprising the steps of: sensing whether the seat is occupied by use of a weight-sensitive sensor and relaying the information to a controller configured to automatically regulate the operation of one or more thermoelectric modules and fans; activating at least one thermoelectric module in response to sensing the status of the weight-sensitive sensor to provide temperature conditioned air; activating at least one fan to pass the temperature conditioned air to the variable temperature seat; sensing a temperature and relaying the temperature information to the controller; and automatically changing electrical power to the thermoelectric modules, by varying a duty cycle of power to the modules, when operated in a cooling mode after the temperature of the temperature conditioned air is below a minimum cooling temperature and after a maximum amount of time has passed since the system was placed in a cooling mode of operation.
 25. A system for controlling the temperature climate in a variable temperature occupant seat comprising: an occupant seat having at least one conduit configured to distribute a sufficient amount of temperature conditioned air through the seat to increase a seat occupant's thermal comfort; at least one heat pump for providing temperature conditioned air, each heat pump being in fluid communication with the conduit in the seat and having a fan to move thermally conditioned air to the conduit in the seat; a controller in electrical communication with the heat pump and fan and controlled to provide temperature conditioned air to increase the thermal comfort of a seated occupant; at least one sensor for monitoring the operation of at least one heat pump, or monitoring the temperature of the air passing through the heat pump, or monitoring ambient air temperature and providing a signal correlated to that operation or monitored temperature to the controller; means for automatically operating the controller to provide thermal comfort to the seated occupant, and to control heating and cooling functions of the system to reduce occupant discomfort and adverse physiological response; and an indicator located in the seat for detecting the presence of the seat occupant, the indicator being in communication with the controller. 